Opioids Linked to Unusual Cases of Sudden Memory Loss

The hippocampus is part of the brain responsible for forming and storing memories. In fourteen cases, opioid use has been linked to complete shutdown of blood flow to the region.

Credit Gray's Anatomy / Wikimedia Commons, public domain

As if the epidemic of opioid addiction and overdoses isn’t bad enough, a new study finds that – in a very small number of cases – opioid use has been linked to profound memory loss. It’s kind of a medical mystery story that started in November of 2015. That’s when Dr. Jed Barash, a neurologist at Lahey Hospital and Medical Center in Burlington, MA, brought four patients to the attention of officials at the Department of Public Health.

All four had showed up at the hospital with amnesia and, in each case, an MRI of the brain had shown a complete lack of blood (and oxygen) flow to the hippocampus region on both sides of the brain.

“He had a very convincing story about how unusual it was to see four cases of this condition in a short space of time compared to what was in the world literature that he had reviewed,” said Dr. Alfred DeMaria, Medical Director and State Epidemiologist with the Bureau of Infectious Disease and Laboratory Sciences. “It did catch my attention, and it did seem like something worth pursuing.”

The Department of Public Health did pursue it, asking doctors around the state for any similar cases they had encountered. In the end, they identified ten more patients with the same MRI diagnosis.

So far, the only commonality is a history of opioid use, but there are plenty of open questions. Why these fourteen, out of the thousands of MA residents using opioids? Why were most of them men? And, importantly, do these patients recover their ability to form memories?

Barash and DeMaria recently published their preliminary findings in hopes of spurring more investigation. They chose to publish in the Centers for Disease Control’s Morbidity and Mortality Weekly Report, because it was the fastest way to get the information out to the medical community.

They’re not suggesting every person with a history of opioid use get an MRI. They are hoping that doctors – and, for that matter, families and friends – will work harder to identify and follow up with opioid users with sudden, severe memory deficits. For example, DeMaria says a simple set of questions could help distinguish between normal confusion after an overdose, and the profound memory impairments he and Barash have reported.

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